Method of sandblast carving



Aug. 17, 1943. s'. CHRUMA METHOD OF SAND BLAST CARVING Fild Feb. 5; 1941 INVENT OR,

fifep/ien Chm/ma exposed granite surface.

Patented Aug. 17, 1943 ,UNITED, STATES PATENTv OFF-ICE V 2,321,019" a H METHOD OF SANDBLAST oAnvmG Stephen Ohruma, Kansas City, Kans, v Application February 3, 1941, Serial No 377,121 f s cranes. (cm- 9 V This invention relates to improvements in the method of sand blast carving and has particular reference to shape carving of stone, .granite, marble, etc. wherein reliefdesigningv is produced by undercutting portions of a design toimitatev actual structures.

blasting has; been used. taprobut not to produce undercut the use of chisel and mallet.

Heretofore sand duce relief carving work, which requires hand cutting is very slow andbecause; of the cost is; prohibitive for use in designing most monuments. V v Z The present invention contemplates the use of the sand blast process to produce the desired undercut relief worlgat a rapid rate and at a'cost far lessthan the cost oftool undercutting:

In carrying out my method thesurface'to be carved is covered with a sheet of'jcornpressible'and :yieldin g rnaterial which is secured in position by an adhesive. The design to be produced-iscut carved or cutaway by the action of sand blasting. By thelterm sand blasting" is meant. the abrasion of .a. surface by forcing a" current of air,

carrying an abrasive the'reagainst. .Theabrasive being sand, carborundum, steel or any other'material of greater hardness than the material to be carved. The "surface l2 to becarved is shown as of planar shape; however itmight-be of any other 'form without interferingwith themethod of carving? The surface to be carved is'covered with a sheet or coat of yielding material, a soft .rubberfgelatinous material, etc.', which is substantially immune'to'the sand blast, due to its compressibility when engaged by the rapidly movi g particles of abrasive; This surface covering may be of an adhesive nature suitable to adthrough the coating sheet to present a pluralit of separate sheet sections.

1 Other objeets of this inventionis the methodof shape-carving granite or the like by the sand blast process to produceundercut relief designs at a much more rapidrate than has beenpossible I with the old methods now in use.

g The drawing forming a part of this application shows atypical design and the various steps involving carrying out this method of sand blast carving, and like characters designate similar :partsthroughout the several views Figure 1 is a sectionalview pf, ablock of ite or any other hardmaterial suitable for sand blast carving having a surface to be carved, cov- 'ered with a sheet of yieldable material. 3

V Fig. 2 is a view similar to that shown in'Fi'g. 1 whereon the desired designhas been cut through the yieldable sheetcovering and a po rtio n of the sheet peeled off topermit sandblasting of the right angles tothe surface to be carvedtop'rm duce a substantially vertical -wall adjacent the surface to be undercut.

Fig. 4 is another view of the granite block' showing the gun nozzle positioned to directthesand to form an undercut below'the covered surface of theblock. V l 1. 5 is a plan view of the block with the yieldable cover sheet positioned thereon and having the design cut therethrough. 7

Fig. 6 is a plan view of the block withthe desired design formed 11111175 surface portion'.'

Fig. 7 is a cross-sectional view taken on line VII--V'II of Fig. 6.

Referring to the drawing, the numeral I0 designates a block of granite, marble, stone or any other relatively hard material adapted to be here to the, surface to be carved or it may be secured thereto by means of an applied adhesive.

The desired design [4 is now cutfthroughthe isheet covering as shown in Fig. 5. The slits l6 f constitutingja line. drawing of the design segragates thevariousportions18,- 22, 24, 26, 28-, 30, 32, 34, 36, 38 and Ill so that they may-beseparately and selectively peeled from. the surface to be carved, so as to expose only the part to be fcaryed while other partsremain covered to facilitate proper carving. The covering strip I8 is first removed andjanputline groove 42 is sand blasted to the desired depth. a

In order to properly carve'the design such as shown it is necessary thatthe undercut portions be directed toward a common center and" it is therefore found best practice to first carvethe outer portions and work toward said common center. After the outline groove 42 has been carvedit will be considered that the cover portion 26 is next removed to permit the formation of one ofthe outside petals of the rose design shown. The sand blast gun nozzle 44 through which the, mixture of abrasive and air; under pressure is' delivered to the work, is now directed substantially vertically to the surface to b carved to produce-a wall in register-with thefedge of the adjacent coversheet beneath'which animdercut is to be formed in the granite block. 7 The formation of the vertically disposed ,wall

46 in alignmentwith the adjacent cover, sheet. "portionis very. important in that it makes 130ssibletheundercutting of the'block at this point ;'without interfering with th adherence of the 1 surface covering'of the block to thesurface' to .be ,carvedsfl. After the formation of 'wall- 46' the sand blast gun 'noz'zlecan be positioned as shown in Fig. l 'todi'rect' the v abrasive material obliquely 1 fto th'esurface to becarved and in the direction of the1wall ,4liv .toflform an undercutfly This undercut can'be produced: to any desired depth and will extend beneath the sheet-protected face of the block.

Should the operator attempt to undercut before producing the vertical wall 46 the abrasive particles would be directed to the joint between the cover sheet and the surface of the block thus tending to separate the sheet from the block and mutilating the surface of the block thus exposed. With the wall 16 formed the particles of abrasive will be directed downwardly and inwardly against wall 46 and will not interfere with the position of the sheet covering of the block.

It will be noted that the surface 50 will represent the upper surface of the outside rose petal while the surface 52 of the undercut will represent the under side of one of the second row of petals. This same operation is repeated by successively removing cover portions 24, 22, 20, 39, and 28. The operator can now remove sheet cover section 35 to form a vertical wall adjacent the cover portion 40 so as to permit undercutting therebeneath. Likewise cover sections 3!, 32, and

38 are successively removed to permit formation of the remaining second row of petals.

The center section of the sheet covering is now removed and the surface sand blasted to*pro duce the central recess. After the entire covering for the design has beenremoved the operator may further sand blast the design to produc the desired rounded edges of the petals. That portion of the cover sheet outside the deswnis now removed and the'surface carving is complete. It is quite apparent that other designs might require outwardly directed undercutting or in some instances the direction of undercut might be varied in the same design.

It is quite apparent that the principal requirement in this method of sand blast carving is that a substantially vertical wall be first produced in the body of the block to be carved in order to make it possible to produce the undercut. As Stated above heretofore sand blasting designs of this character have been carried out without any undercuts due'to the fact that they could not be produced by any of the then known methods.

With this type of sand blast carving wherein the component particles of the design are more nearly simulated the appearance is g eatly improved due to the shades and shadows produced which more nearly resemble those of'the actual thing being depleted.

Undercatting on designs of this characterhas been accomplished by means of chiselsand mallet, however this type of work is slow and tedious and is too expensive for commercial use in the construction of monuments. While I have shown, by one design, wherein the present method is used, however its application to practically any of the designs wherein undercut work is -desirable it may be used to an advantage.

Having thus described the invention, what is claimed as new and desired to be securedby Letters Patent is:

1. The method of sand blast carving which consists in coating the block surface to be carved with yieldable coating, cutting the desigi to be carved through said coating to present a plurality of segregated portions of the coating, peeling off one portion of the coatingtoexpose the block surface, directing a sand blast at an acute angle against said exposed surface to form an undercut beneath the adiacent surface coating, then removing the surface covering portion above said undercut and sandblasting the newly exposed surface. a

2. The method of sand blast carving which consists in coating the block surface to be carved with yieldable coating, cutting the design to be carved through said coating to present a plurality of segregated portions of the coating. peeling off one portion of the coating to expose the block surface, sand blasting said exposed surface to form a relatively shallow vertical wall in alignment with the adjacent coating portion, sand blasting said block at the juncture of the vertical wall with the adjacent carved surface to form an undercut beneath the adjacent coated surface, successively removing the remaining coating portions and sandblasting the block surface until the design is completely carved.

3. The method of sand blast carving which consists in coating the block surface to be carved with yieidabie coating, cutting the design to be carved through said coating to present a plurality of segregated portions of the coating, peeling off one portion of the coating to expose the block surface, sand blasting said exposed surface to form a relatively shallow vertical wall in alignme'rrt with the adjacent coating pardon, sand blasting said block at the juncture of the vertical wall with the adjacent carved surface to form an undercut beneath the adjacent coated surface, removing the cover coating portion above said undercut to expose the block surface, sand blasting the last exposed surfaceto reduce the tinckness of the block materialbetween said undercut and the block surface thereabove, auccessively removing the remaining coat portions and carving the exposed surfaces until the design is completely carved.

4. The method of sand blast carving which consists in coating the block surface to be carved with a sheet of yieldable material: cutting the design to be carved through said sheet; peeling the sheet covering from one portion of the surface to be sand blasted; sand blasting said ourface by directing the sand at mama"! fi t angles thereto until relatlveiy shallow vertical walls are formed along the edges to beundemrt; then directing the sand blast at an acute angle to the surface to be carved and toward saidshallow vertical walls, whereby an undercut is formed in the block beneath the then sheet covered portion of the surface, repeating these undercutting stepsuntfi the undercutting of all portions of the surface to be carved is completed their removing the remaining sheet covering. 4

5. Bio method of sand blast carving 1inch consists in coating the block surface to be airved "withyieldable coating, cutting the design to be carved through said coating to present a pierai'ity of segregated portions of the coating, peeli'ngoi'! one portion of thccoablngtoexpose the block surface, directing a sand blast at an acute angle against said exposed surface to form an undercut at any desired depth beneath the then sheet covered portion of the surface; peeling-oil another adjacent portion of the design cover sheet and repeating the sand blasting operations, repeating this peeling off and the sand bhsflng operaticrm until all the undercutting is completed, then removing the remaining design cover sheet portions and sand blasting these uncovered surfaces. v 

